NSURL with JSON returns null - ios

Question

I'm keep getting a (null) error when I try to build my NSURL to open another app.
The URL should be
ms-test-app://eventSourceId=evtSrcId&eventID=13675016&eventType=0&json={"meterresults":[{"clean":"2","raw":"2","status":"0"}]}
but when I try to build my URL it's always null.
At first I thought it has something to do with the URL itself, but it's the same as I got it from the example here.
Another thought was that IOS got some problems with the double quotes in the JSON, but I replaced them with %22, but this doesn't work either.
Here is the code, where I build the URL:
NSString *jsonString = [NSString stringWithFormat:#"{%22meterresults%22:[{%22clean%22:%22%#%22,%22raw%22:%22%#%22,%22status%22:%22%#%22}]}", cleanReadingString, rawReadingString, status];
NSLog(#"JSON= %#",jsonString);
//Send the result JSON back to the movilizer app
NSString *eventSourceId = #"evtSrcId";
NSString *encodedQueryString = [NSString stringWithFormat:#"?eventSourceId=%#&eventID=%d&eventType=0&json=%#",
eventSourceId, _eventId, jsonString];[NSCharacterSet URLQueryAllowedCharacterSet]]
NSString *urlStr = [NSString stringWithFormat:#"%#%#",
[_endpointUrls objectForKey:[NSNumber numberWithInt:(int)_selectedEndpoint]],
encodedQueryString];
NSURL *url = [NSURL URLWithString:urlStr];
I don't know where I'm wrong and I would be glad if someone got any idea.
Thanks in advance.

Answer 1

You should really be using NSURLComponents to create URLs rather than trying to format them into a string.
NSDictionary* jsonDict = #{#"clean": #"2", #"raw": #"2", #"status": #"0"};
NSData* jsonData = [NSJSONSerialization dataWithJSONObject:jsonDict options:0 error:NULL];
NSString* jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
NSURLComponents* components = [[NSURLComponents alloc] init];
components.scheme = #"ms-test-app";
components.queryItems = #[
[[NSURLQueryItem alloc] initWithName:#"eventSourceId" value:eventSourceId],
[[NSURLQueryItem alloc] initWithName:#"eventID" value:#(_eventId).stringValue],
[[NSURLQueryItem alloc] initWithName:#"json" value:jsonString]
];
NSURL* url = components.URL;
Once you build the URL that way, it becomes apparent that your string doesn't have a host portion (or more accurately, one of your parameters is being used as the host portion).
The other comments about not being able to send JSON as an URL parameter are incorrect. As long as the system on the other side that is parsing the query string can handle it, you can send anything you want as an URL parameter.